The present invention relates generally to aqueous amine-containing lubricant solutions. More particularly, the present invention relates to such lubricant solutions and their use as a conveyor belt lubricant for the lubrication of conveyor belts for bottles.
Lubricants are employed in applications in which good gliding contact between solid surfaces, for instance glass and metal or metal and metal, must be ensured. Amine-containing synthetic lubricants are, in general, known for a variety of such applications. See, for example, U.S. Pat Nos. 3,372,112, 3,814,212, 4,549,974, GB1294038, EP-A-0032415, W087/07638 and JP-LO-82/205494, all of which are incorporated by reference herein.
Additionally known are amine-containing cleaning solutions for, e.g., milk equipment and silver. See FR-A-2602955 and U.S. Pat. No. 3,468,804, both of which are also incorporated by reference herein.
Lubricants are also frequently used in bottle filling and conveying plants, where they are applied to the conveyor belts to ensure the trouble-free conveyance of bottles on the conveyor belt. When used as such, the lubricants are also referred to as belt lubricants.
In many typical systems, a soap such as a potash-based soft soap is used as the belt lubricant. A problem of such soaps is that they have a tendency to form poorly-soluble precipitates with cations present in hard water, such as calcium, requiring the addition of sequestering agents or the use of soft water.
As a substitute for the soaps, a variety of synthetic belt lubricants including certain amine compounds have been described in the literature. See, for example, DE-OS-3631953 (U.S. Pat. No. 4,839,067), JP-LO-74/010794, JP-LO-89/096294, U.S. Pat. Nos. 4,521,321, 4,604,720, ZA77/7258, ZA83/7963 and AU-A-10004/83, all of which are incorporated by reference herein. These synthetic belt lubricants are generally an improvement over the aforementioned potash-based soaps; however, in some cases they tend to form poorly-soluble precipitates with polyvalent anions present in hard water, such as carbonates and sulphates, which manifests itself in the clouding of the lubricant solution. For that reason the behavior of lubricants in anion-containing water is sometimes called clouding behavior.
Since the precipitates formed can cause breakdowns as a result of deposits in blind zones or clogging of nozzles, they must be removed regularly, mostly once a day, by cleaning the plant. Heavy clouding behavior of a lubricant solution is especially critical in places where the water contains a high proportion of polyvalent anions. In fact, the problem in some places may be so great that soft water is used instead of tap water, or substantially more frequent cleaning is required.